The present invention refers to a restraining device comprising a seat belt and a belt force limiter.
In particular in automotive vehicles and aircraft, restraining devices serve to secure the passengers in case of a vehicle crash. In a heavy collision, the tensioning forces of the belt may become strong enough for the belt to cause injuries to the secured passengers. To avoid such injuries, belt force limiters are used that momentarily relax the belt when belt tension force peaks occur, so as to alleviate the tension force peaks. Such belt force limiters are arranged at one belt end and release the belt end when a predetermined belt tension force is exceeded. Thus, the belt force limiter is arranged remote from the belt portion on which the belt force acts on the passenger and at which this force is to be limited. Thereby, the belt force limitation takes effect in the belt portions at a person's body in a reduced manner and only with a delay. Further, belt force limiters are in most cases integrated in a belt winding mechanism, which is technically rather complicated. From German Patent 39 00 066, a belt force limiter is known that has an elastic absorption member. The elastic absorption member responses proportional to the occurring tension forces, which is why it is not suited for exclusively absorbing tension force peaks. From German Patent 39 33 762, a belt force limiter is known in which the absorption member is deformed plastically. Again, the absorption member yields almost proportional to the tension force present so that in case of a delayed occurrence of tension force peaks, the absorption capacity may already be used up. German patent 75 00 059 discloses an absorption member arranged along a belt and bridging a belt loop. Since the belt loop is relatively large, the belt has a large lengthwise yield when the absorption member is destroyed so that a second tension force peak builds up.